[42.20] A Possible Merging Companion to Cygnus A

Different lines of evidence indicate that the powerful FR II
radio galaxy Cygnus A harbors a heavily extincted quasar.
However, until now, no direct evidence has been found
indicating that the nuclear activity may have been triggered
by a strong interaction or merger. We recently obtained Keck
adaptive optics imaging and spectroscopic observations of
the core of Cygnus A of unprecedented resolution and depth.
These images show a secondary point source 400 pc away from
the radio nucleus. The colors and near infrared spectra of
this object rule out the possibility that it may be a
foreground star. We discuss the possibility that the object
may instead be the dense, gas stripped core of a low
luminosity merging galaxy that has thus far survived the
merger with the giant elliptical host to Cygnus A.

This work was performed under the auspices of the U.S.
Department of Energy, National Nuclear Security
Administration by the University of California, Lawrence
Livermore National Laboratory under contract No.
W-7405-Eng-48